| Ono Toyo Golf Club | Ono | Hyogo |  Japan | inactive |
| Onomichi Country Club - Uneyama Course | Sera | Hiroshima | Japan | inactive |
| Onomichi Golf Club | Mihara | Hiroshima | Japan | inactive |
| Onomichi Uzushio Country Club | Onomichi | Hiroshima | Japan | inactive |
| Onondaga Golf and Country Club | Fayetteville | New York |  USA | inactive |
| Onsjö Golfklubb | Vänersborg | Västra Götaland |  Sverige | inactive |
| Onsøy Golfklubb | Manstad | Østfold |  Norge | inactive |
| Ontake | Kani | Gifu | Japan | inactive |
| Ontario Country Club | Ontario | New York | USA | inactive |
| Onteora Club | Tannersville | New York | USA | inactive |
| Ontonagon Golf Course | Ontonagon | Michigan | USA | inactive |
| Onuma Kokusai Country Club | Kayabe | Hokkaido | Japan | inactive |
| Onuma Lake Golf Club | Kayabe | Hokkaido | Japan | inactive |
| Onward Mangilao Golf Club | Mangilao | Guam |  Guam | inactive |
| Onward Talofofo Golf Club | Talafofo | Guam | Guam | inactive |
| Onwentsia Club | Lake Forest | Illinois | USA | inactive |
| Onyx | Grand Blanc | Michigan | USA | inactive |
| Oodate Country Club | Oodate | Akita | Japan | inactive |
| Ooka Golf Club | Kinosaki | Hyogo | Japan | inactive |
| Oonodai Golf Club | Akita | Akita | Japan | inactive |
| Oosaki Golf Club | Shida | Miyagi | Japan | inactive |
| Oost-Zuid | Nunspeet | Gelderland |  Nederland | inactive |
| Oost-Zuid | Groesbeek | Gelderland | Nederland | inactive |
| Oostwoud-Westwoud | Benthuizen | Zuid-Holland | Nederland | inactive |
| Ootacamund Gymkhana Golf Club | The Nilgiris | Tamil Nadu |  India | inactive |
| Ootaka | Housu | Ishikawa | Japan | inactive |
| Ootawara Golf Club | Nasu | Tochigi | Japan | inactive |
| Ooyodogawa Golf Course | Miyazaki | Miyazaki | Japan | inactive |
| Opal Cove Resort Golf Course | Coffs Harbour | New South Wales |  Australia | inactive |
| Open | Cotgrave | Nottinghamshire |  England | inactive |
| Open | Dongguan | Guangdong |  Kina | inactive |
| Open | Fingal | Victoria | Australia | inactive |
| Open 9 | Myrtle Beach | South Carolina | USA | inactive |
| OPEN GOLF St. Johann Alpendorf | Sankt Johann im Pongau | Salzburg |  Østerrike | inactive |
| Open Golf Zandvoort | Zandvoort | Noord-Holland | Nederland | inactive |
| Open.9 Golf Eichenried | Moosinning | Bavaria |  Tyskland | inactive |
| Openbare Golfbaan Kralingen | Rotterdam | Zuid-Holland | Nederland | inactive |
| Openbare Golfclub Dronten | Dronten | Flevoland | Nederland | inactive |
| Oporto Golf Club | Espinho | Beira Litoral |  Portugal | inactive |
| Opotiki Golf Club | Opotiki | Bay of Plenty |  New Zealand | inactive |
| Oppdal Golfklubb | Oppdal | Sør-Trøndelag | Norge | inactive |
| Oppegård Golfklubb | Oppegård | Akershus | Norge | inactive |
| Oppenheimer Golf Club | Welkom | Free State |  Sør-Afrika | inactive |
| Opunake Golf Course | Opunake | Taranaki | New Zealand | inactive |
| Oquirrh Hills Golf Course | Tooele | Utah | USA | inactive |
| Ora Country Club | Jeju | Jeju |  Sør-Korea | inactive |
| Orange | Savoy | Illinois | USA | inactive |
| Orange | Parrish | Florida | USA | inactive |
| Orange | Anseong | Gyeonggi | Sør-Korea | inactive |
| Orange | Tomioka | Gunma | Japan | inactive |